Semiconductor elements such as for example semiconductor laser diodes represent an essential basis of modern information and data processing systems and future display systems. While such laser diodes are available for the infrared, red and blue-violet spectral range, it has hitherto not been possible to produce a green semiconductor laser which enjoys an adequate service life. The most promising approach in terms of embodying a green semiconductor laser is based on II/VI semiconductor structures with ZnTe-bearing cover layers, but the service life of those components is still not satisfactory for commercial use (see E. Kato, H. Noguchi, M. Nagai, H. Okuyama, S. Kijima, and A. Ishibashi, Elec. Lett. 34, 282 (1998)).
Hitherto, those II/VI semiconductor laser structures with ZnTe-bearing cover layers were contacted by metals, typically palladium which is deposited on the semiconductor surface. Then platinum and/or gold are deposited on the palladium layer (see M. Haase, J. Qui, J. M. DePuydt, and H. Cheng; Appl. Phys. Lett. 59, 1272 (1991), M. Ozawa, F. Hiei, A. Ishibashi, and K. Akikmoto, Elect. Lett. 29.503 (1993) and S. Kijima, H. Okuyama, Y. Sanaka, T. Kobaayshi, S. Tomiya, and A. Ishibashi; Appl. Phys. Lett. 73; 235 (1998)). The operation of applying those layers is carried out by means of vapor deposition, for example thermal vapor deposition or electron beam vapor deposition. The use of lithium nitride in II/VI semiconductor technology is hitherto only known as a doping material, in which case the material is diffused in at temperatures of between 350° C. and 570° C. (see T. Honda, S. W. Lim, K. Yanashima, K. Inoue, K. Hara, H. Munekata, H. Kukimoto, F. Koyama and K. Iga, Jpn. J. Appl. Phys., 35, 3878 (1996) and S. W. Lim, T. Honda, F. Koyama, K. Iga, K. Inoue, K. Yanashima, H. Munekata and H. Kukimoto, Appl. Phys. Lett. 65, 2437 (1994)). A laser use presupposes a doping concentration of at least 1018 cm−3. That was only approximately attained at a temperature of 470° C., with that process. That temperature however would trigger off diffusion effects (for example of Cd) in the deeper laser layers, so that the consequence would be destruction of the laser structure. Therefore that process cannot be applied in laser technology.
The heat which is generated during electrical operation of the laser diode, for example due to the contact resistance at the contact, contributes substantially to the degradation of the entire structure.